1. Field
The following description relates to a liquid crystal display device. The following description also relates to a liquid crystal display device with a repair function and a repair type data format structure with an improved repair function by providing a new data format structure, integrating channel data for channel drive and repair amplifier data, which is used for repairing a defect of a liquid crystal line.
2. Description of Related Art
Generally, liquid crystal display devices, such as Liquid Crystal Display (LCD) or Organic Light Emitting Diode (OLED) displays, show an image by using a switching element, a plurality of thin film transistors, and a pixel electrode, which is connected to a thin film transistor, that exist in a matrix.
The thin film transistor includes a gate electrode, an active layer and a source electrode and a drain electrode and herein, the gate electrode and the source electrode, share one transverse line or one longitudinal line. The transverse line is generally called as a gate line, as the transverse line transmits a pulse voltage that drives a gate electrode. The longitudinal line is called as a data line, as the longitudinal line transmits a signal voltage that drives a source electrode.
When a pulse is scanned into the gate line, a pulse is applied to the gate electrode of thin film transistor that is a switching element, and when a signal voltage is applied to the data line, a signal is applied to the source electrode of the thin film transistor. At this time, a voltage, which may drive a liquid crystal, is applied by an arbitrary source electrode of a signal of the gate electrode, and when a voltage, which is smaller than the liquid crystal driver voltage, is applied to the rest, a pixel, only applied with a liquid crystal driver voltage, will operate. It is possible to drive all pixel electrodes of a liquid crystal display device by applying a pulse in rotation to the all gate electrodes and by applying a signal voltage to the relevant source electrodes by this operational principle.
However, a defect that occurs in an opened liquid crystal line, that is, a gate line or a data line, is potentially the main reason of a process yield decrease in a liquid crystal display device manufacturing process. For example, when one of liquid crystal lines is disconnected, all of the thin film transistors connected with the opened line become inoperative, which soon causes a fatal defect in a liquid crystal display element.
Therefore, countermeasures regarding a defect of the occurrence of an opened liquid crystal line have become an important issue. In an effort to solve this problem, measures using a repair line were drawn up, which are presented with reference to FIG. 1.
FIG. 1 is a schematic plan view of a liquid crystal display device according to an example.
Accordingly, a liquid display element 100 is illustrated, which displays information on a liquid crystal display device as shown in the drawing. In the example of FIG. 1, a liquid display element 100 is an LCD panel or an OLED panel.
An Integrated Circuit (IC) 110 that drives a liquid display element 100 is included. In a case in which a defect of an opened liquid crystal line occurs, a display driver IC 110 is designed to include built-in two repair amplifiers 120, 130 that provide the ability to repair the relevant liquid crystal line.
A printed circuit board (PCB), not shown in the drawing, is placed on an output terminal of the repair amplifiers 120, 130. Hence, the repair amplifiers 120, 130 are connected with repair lines 122, 132 via PCB lines 121, 131. In the drawing, PCB lines 121, 131 and repair lines 122, 132 are each shown as one line. However, PCB lines 121, 131 are a line formed on the portion of a printed circuit board that are located in the vicinity of a liquid crystal display element 100.
In this kind of liquid crystal display device, when an arbitrary liquid crystal line is opened, a liquid crystal line is repaired using repair lines 122, 132.
However, the liquid crystal display device of FIG. 1 confronts the following issue.
The structure of FIG. 1 has a form that has to directly apply the grayscale of a relevant liquid crystal line from outside in case a liquid crystal line is opened. In other words, since the grayscale of an opened liquid crystal line is not known, the grayscale is preferably applied via an input terminal of repair amplifiers 120, 130. Moreover, a decoder that respectively responds with each repair amplifier, and a channel amplifier that drives a liquid crystal display device, is to be provided. These structures become a cause of complexity of a liquid crystal display device.
Additionally, in FIG. 1, an output of the repair amplifiers 120, 130 that is potentially to be sent along lines across the PCB that is formed on a circumference of a liquid crystal display device 100, as repair amplifiers 120, 130 are placed in a middle section of a display driver IC 110. This causes a problem of increased complexity of the PCB.
Moreover, when the repair lines 122, 132 lengthen, a resistance of the repair lines 122, 132 increases accordingly, and hence, causes a problem of generating a loss in the transmitted driver signal that is delivered via the repair lines 122, 132. In this case, if a liquid crystal display device 100 size grows, repair lines 122, 132 lengthen but due to limitations of the driving ability of a display driver IC 110, an opened liquid crystal line may be expected to be irreparable in some cases.
Further, because according to the structure of FIG. 1, since repair lines 122, 132, formed on a border of a liquid crystal element 100, are provided only singly each, an additional signal to select either a pixel electrode defect or a liquid crystal defect, is required. For example, when the cause of defect that is generated in one portion is a pixel electrode, a driving signal is to be transmitted according to the defect cause, whereas a driving signal repairing the liquid crystal line is to be transmitted when a cause is a liquid crystal line.
Thus, circuit structure complexity increases in the structure of FIG. 1.
Moreover, a control line repair amplifier Control DC line is also required to apply a control signal to control on/off operation of a repair amplifier in alternative approaches.
Thus, measures for easier repair are advantageous when a defect in a liquid crystal line of a liquid crystal display device occurs.